Galaxy s6 edge extremely hot and I had it on table doing absolutely nothing?

It will probably be updating apps and one or more could be non compliant.

You should Google for it and near the top will be this:

"Solution 1: Third party app cause overheating

It could be that an app is responsible for the Galaxy S6 overheating. To check, you should start the Smartphone in safe mode. If the problem is gone when using the Safe mode, then you know what the cause is. In this case you should uninstall all third party apps or just perform a factory reset.

To start the safe mode, you have to turn off your Samsung Galaxy S6 first.

Press the Power button and wait until you see the beautiful Galaxy S6 Logo screen.

When the logo shows up on the screen you have to immediately hold the Volume down button until the Home screen loads.

In the left corner it should say “Safe Mode”.

Solution 2: Wipe cache partition

When the Samsung Galaxy S6 gets hot, then you should run the wipe cache partition function. This function has already helped some users to solve the overheating problem on the Samsung Galaxy S5.

Turn off your Galaxy S6

Press and hold down the Power, Volume up and the Home buttons together.

After the beautiful Samsung logo appears you should see a blue recovery text at the top.

Use the Volume up and down keys to scroll in the Recovery menu.

Mark the entry “Wipe cache partition” and start it with the Power button.

This process will usually take some seconds and the previously display menu will appear, after it finished.

Finish the process with “Reboot system now” and you done.

Don’t worry, this function will not delete any personal data on your Samsung Galaxy S6. This method only deletes temporary system files and no personal data like pictures, videos, contacts and so on.

If nothing helps and the Samsung Galaxy S6 still becomes very hot when using it, you should take the smartphone back to the store where it can be checked for any damage."

That's what Samsung's do.... I have the same problem with my Galaxy s5. Try calling your cell phone provider, and see if they can give you another one for free (that is if you have a warranty on it)